In Line Derailleur

ABSTRACT

The present invention is a derailleur comprising: a base plate disposed between the perimeter of a drive sprocket nest and a pedal sprocket; a chain guide attached to said base plate for moving a chain laterally causing said chain to move form sprocket to sprocket in a sprocket nest; a chain guide surface included in said chain guide for causing said chain to contact over ½ the perimeter of said pedal sprocket decreasing the likelihood of the chain slipping off said sprocket; and, a tension member attached to said base plate for removing slack in a chain as the chain moves from a larger sprocket to a smaller sprocket.

FIELD OF THE INVENTION

This application relates to a speed changing device for rider propelledvehicles using a chain drive and a sprocket nest with a plurality ofdifferent sized sprockets. The sprocket changing device is a derailleursystem in line with sprocket nests including a chain slack take-upmechanism.

BACKGROUND OF THE INVENTION

A rider propelled vehicle is generally understood to be typically a twowheeled vehicle with a front free rolling, steerable wheel and a rearfree rolling, non-steerable wheel, connected to each other by a frameincluding a rider platform positioned between the wheels on which therider can support himself. To move, the rider can actuate pedal toprovide rotational force on the rear wheel producing locomotion. Thislocomotion process has been employed for bicycles for quite some time asshown in U.S. Pat. No. 540,977 issued on Jun. 11, 1895.

The limitation to the initial bicycle design was that the pedal wereconnected to the drive wheel either directly or by a chain. However,this connection was typically a single gear connection. Attempting toimprove the efficiency of the connection includes the advent of thesprocket nest and derailleur system as shown in U.S. Pat. No. 3,535,950issued on Oct. 27, 2970. In the reference, the derailleur is disposed ator near the rear sprocket nest.

The derailleur system currently used in bicycles has been engineered toallow the chain to smoothly move to an adjacent sprocket within thesprocket nest at selected locations around each sprocket. Each sprocketis modified to provide clearance for chain shifting with a smallplurality of reduced sized chain pickup teeth with modified shape atselected locations on the sprocket, but with adjacent normally sizedteeth providing adequate chain grip and strength around the rest of thesprocket's outer periphery or circumference.

The chain travel is directed by a movement of the derailleur guiding thechain from the sprocket it is on and feeding the chain onto an adjacentlarger sprocket when decreasing the speed or a smaller sprocket whenincreasing the speed.

The bicycle derailleur devices are physically mounted on the frame ofthe bicycle and its movement is generally operated by a guide wire orcable extending from a shifting lever attached on the handle bar to thederailleur. When the rider selects a new sprocket, he moves the levermoving the wire or cable which in turn repositions the derailleur toeffect a sprocket change. The derailleur is a sophisticated device thathas a fixed structure attached to the frame or rear axle and a movablestructure that is held in position by at least one double pivot withmultiple heavy duty springs that allow the movable elements to rotate ormove in the path of a parallelogram created by two opposing plateshinged to move parallel relative to the other. This movement enables thechain guide portion of the derailleur to move relative to the sprocketnest in a relatively uniform path in relation to the guide and thesprockets while minimizing twisting the chain.

In order to function properly, the chain slack that exists when thechain is on the sprocket must be taken up. The amount of chain slack isreduced as the chain moves to larger sprockets. In bicycles, thederailleur chain guide system is positioned to extend well below theaxle and frame. This enables the chain to serpentine through the lowhanging derailleur guide system by having the chain extend well belowthe largest of the sprockets. Due to this limitation, derailleurs arenot available for vehicle such as scooters which include much smallerwheels and tire and therefore have insufficient clearance for thetypical derailleur.

Recently, a new generation of scooters and bicycles has been developedwith reciprocating foot pedals such as U.S. Pat. No. 8,128,111. Thesevehicles, particularly the scooters, have frames that have a very lowcenter of gravity to make the vehicles more stable. The frames are solow to the ground that the prior art derailleurs conventionallypositioned below the rear sprocket nest are virtually useless.Nevertheless, these vehicles need a shifting device to allow the riderto selectively change speeds. Further, positioning the derailleuradjacent to the rear sprocket nest is not advantageous for such avehicle as a scooter. It would be preferred to have a derailleur that isdisposed between the front and rear sprocket nests.

Further, the typical derailleur can only actuate one sprocket nest at atime. As such, for a vehicle such as a bicycle with a sprocket nest atthe rear wheel and a sprocket nest at the pedal assembly, twoderailleurs are required. Dual derailleurs are simply too bulky andcomplicated for today's' scooter. Further, placing the derailleuradjacent to the rear wheel requires that the pedal of a scooter such asshown in U.S. Pat. No. 8,128,111 be too high over the rear wheel axle orspaced too far apart to accommodate the traditional derailleur.

Further, the typical derailleur and drive assembly causes the chain tocontact the sprocket only on about one half of the sprocket as shown inU.S. Pat. No. 6,572,500. As can be seen, the chain contacts the rearsprocket on about half of the teeth of the rear sprocket and only abouthalf of the teeth of the front sprocket. This limits the diametersdifferential between sprockets in increasing size on the sprocket nest.If the differential is too large, the chain tends to skip or to evenfall off the sprocket nest.

Therefore, it is the object of the present invention to provide for aderailleur that can be used with a low profile vehicle such as ascooter.

It is another object of the present invention to provide a derailleurthat is disposed between a front and rear sprocket nest.

It is another object of the present invention to provide a derailleurthat can be used to change sprockets for both the front and rearsprocket nest with the need for a dual derailleur system.

It is another object of the present invention to provide a derailleurthat increases the contact surface between the chain and the sprocketsof a sprocket nest.

SUMMARY OF THE INVENTION

The above objectives are accomplished by providing a self-powerednon-motorized vehicle having a frame, a steerable front wheel carried bythe frame, and a rear wheel carried by the frame. The rear wheel linkedto the drive axle, comprising: a drive sprocket nest attached to therear wheel so that when rotational force is applied to the drivesprocket nest the rear wheel rotates causing locomotion; a pedalsprocket carried by the frame and linked to the drive sprocket nest by achain so that when a rotational force is applied to the pedal sprocket,the pedal sprocket rotates causing the drive sprocket nest to rotate; aderailleur carried by the frame and positioned forward the drivesprocket nest and rearward of the pedal sprocket; and, a chain guidethan when the derailleur is moved laterally to a long axis of the frame,the chain moves between sprockets on the drive sprocket nest.

The chain guide can include a chain guide surface which causes the chainto contact over ½ the perimeter of a sprocket of the drive sprocket nestwhen the chain is engaged with the sprocket. A tension member can becarried by the frame causing the chain to contact over ½ the perimeterof the pedal sprocket decreasing the likelihood of the chain slippingoff the sprocket. The derailleur is disposed in a shifting area. Theshifting area can be defined by a line vertically intersecting the axisof the drive sprocket nest, a line connecting generally the topperimeter of the pedal sprocket and the largest sprocket of the drivesprocket nest, a line vertically intersecting the pedal sprocket and aline connecting generally the bottom perimeter of the pedal sprocket andthe largest sprocket of the drive sprocket nest. In one embodiment, theshifting area can be defined by a line vertically intersecting a pointon the perimeter of the largest sprocket of the drive sprocket at themost forward point of the drive sprocket nest, a line connectinggenerally the top perimeter of the pedal sprocket and the largestsprocket of the drive sprocket nest, a line vertically intersecting thepedal sprocket and a line connecting generally the bottom perimeter ofthe pedal sprocket and the largest sprocket of the drive sprocket nest.

The derailleur can include a base plate included in the derailleurwherein the base plate has a first slot and a second slot wherein thesecond slot is generally a “Z” configuration; and, a first pin receivedin the first slot for guiding the base plate along a path and a secondpin received in the second slot for guiding the base plate along thepath. The first slot can be generally a “Z” configuration. In oneembodiment, the first slot and the second slot are offset about 45degrees.

The derailleur can be disposed forward of the perimeter of the largestsprocket of the drive sprocket nest and rearward of the pedal sprocketperimeter. There can be a pedal sprocket and a sprocket in a nestcarried by the frame so that when the derailleur moves in a lateraldirection in relation to a long axis of the frame, the chain moves fromone sprocket to another of the pedal sprocket nest.

DESCRIPTION OF THE DRAWINGS

The invention will be better understood with reference to the followingdrawings that are part of this specification:

FIG. 1A is a side view of the invention placed on a pedal scooter;

FIG. 1B is a side view of the invention placed on a pedal scooter;

FIG. 2 is a top view of the frame showing the pedal sprocket nest,derailleur and drive sprocket nest;

FIGS. 3A through 4D are bottom views of the invention in variousorientations;

FIG. 4 is a perspective view of the invention; and,

FIG. 5 is a top perspective view of the invention.

DESCRIPTION OF THE INVENTION

Referring to FIGS. 1A and 1B, frame 10 includes a drive axle 12 and apedal axle 14. A pedal sprocket 16 is rotatably attached to the frame. Adrive sprocket nest 18 is rotatably attached to the frame rearward ofthe pedal sprocket and includes a plurality of sprockets. A chain 20engages the pedal sprocket and drive sprocket nest so that whenrotational force is applied to the pedal sprocket, the rear drivesprocket nest is rotated. A rear wheel 22 is attached to the drivesprocket nest by a drive linkage so that when the pedal sprocket isrotated; the drive sprocket is rotated thereby rotating the rear wheelproviding locomotion.

A derailleur 24 located in the shifting area 28 includes a chain guide26 attached to the frame and at least partially receives the chain tocause the chain to be moved laterally in relation to the long axis ofthe frame. When the chain guide causes the chain to move laterally, thechain will move from one sprocket in the drive sprocket nest to theadjacent sprocket causing the drive system to change gears. The chainguide, in one embodiment, can include a idler or other surface tosupport the chain upwards.

The shifting area is defined by: (a) a line intersecting generally thetop of the pedal sprocket and the top of the largest sprocket in thedrive sprocket nest, (b) a vertical line generally orthogonal to theaxis of the frame intersecting the drive sprocket nest; (c) a lineintersecting generally the bottom of the largest sprocket in the drivesprocket nest and generally the bottom perimeter of the pedal sprocket;and (d) a vertical line generally orthogonal to the axis of the frameintersecting the pedal sprocket. By having the derailleur disposed inthe shifting area, the derailleur does not require the clearance of thetypical derailleur.

A tension member 30 is shown attached to the frame and includes an idler32 and a spring 34 which biases the idler upwards placing tension on thechain. The tensioning member can be attached to the derailleur or theframe. A tension member guard 36 can be included to prevent the riderfrom being entangled in the chain and tension member idler. A drivesprocket guard 38 can be included to prevent the rider from beingentangled in the drive sprocket nest and chain.

The pedal sprocket 16 is shown. Idler is shown biasing the chain upwardsand causing the chain to contact the pedal sprocket on more than ½ ofits perimeter. Because the chain contacts more than ½ of the perimeterof the pedal sprocket when there is a pedal sprocket nest, the diameterbetween sprockets can be increased over traditional increments. In oneembodiment, the differential between pedal diameters from one pedalsprocket to another is increased by thirty percent over traditionalsprocket nests.

Referring to FIG. 2, the chain guide 26 moves in a lateral directionthereby causing the chain to move from sprocket to sprocket on the drivesprocket nest. In one embodiment, a pedal sprocket nest 42 is includedin place of the single pedal sprocket allowing for more gears. In thisconfiguration, the chain guide causes the chain to move among sprocketson both the drive sprocket nest and the pedal sprocket nest. Inoperation, the chain can be initially positioned around the drivesprocket 44 a and pedal sprocket 46 a. As the chain guide moves in adirection shown as 48, the chain moves from sprocket 44 a to sprocket 44b. As the chain guide continue to move in direction 48, the chain fromto drive sprocket 44 c and then to drive sprocket 44 d. Once the chainhas traveled to the last sprocket in this series, the movement of thechain causes the chain to move from pedal sprocket 46 a to sprocket 46b. When the chain guide moves in a direction opposition 48, the chainwould then move from drive sprocket 44 d, to 44 c, to 44 b and then to44 a. If the chain is on drive sprocket 44 a and the chain guide movesin a direction opposition 48, the chain will move to pedal sprocket 46 afrom 46 b. Therefore, the chain is moved among the pedal sprocket nestand the drive sprocket nest with one chain guide and therefore onederailleur.

Referring to FIG. 3A through 3D, the derailleur base plate 50 isattached to the chain guide 26. A first slot 52 is defined in theforward portion of the base plate and a second slot 54 is defined in arearward portion of the base plate. A first pin 56 is received in thefirst slot and a second pin 58 is received in the second slot. When thecable 60 is tensioned in a direction shown as 62, the base plate alsomove in a direction 62, however, pin 58 and slot 54 force the rearportion of the base plate to move in a direction shown as 64. Direction64 includes two components to its movement, vector 64 a and 64 b. Thevector 64 b moves the chain guide in direction 64 b and therefore causesthe chains to move from one drive sprocket to another. When tension isreleased from the cable, springs such as forward spring 68 a and rearspring 68 b cause the base plate to move in a direction opposite 62thereby causing the chain guide to move is a direction opposite 64causing the chain guide to move the chain from one drive sprocket toanother.

In another embodiment is showing the use of one derailleur to move achain about a pedal sprocket nest and drive sprocket nest. A forwardchain guide 70 is attached to the base plate for causing the chain tomove from one pedal sprocket to another pedal sprocket. The forwardchain guide can include a inside plate 70 a and an outside plate 70 b.The plates of the chain guide can include forward ramps 71 a and 71 b toprevent the chin from catching the chain guide In one embodiment, theplates are curved. The first slot 54 a resembles a “Z” shape with theends angled relative to the long axis of the frame. The second slot 54 balso resembles a “z” shape with the ends generally parallel to the longaxis of the frame. When the base plate is in the inner most position asshown in FIG. 4A, the pin in at the front of the first slot and thefront of the second slot. Referring to FIG. 4B, when the base plate ismoved in a direction shown as 62, the front portion of the base platemoves in a direction shown as 64 b. This causes the chain to also movein the pedal sprocket nest in direction 64 b which causes the chain tomove to another sprocket in the pedal sprocket nest. The rear pin simplytravels in a path parallel to the long axis of the frame and does notcause the chain to move to another sprocket in the drive sprocket nest.

Referring to FIG. 3C, the base plate is further moved in direction 62.This causes the rear portion of the base plate to move in a direction 64b causing the chain to move to another sprocket in the drive sprocketnest. As the front of the base plate simply travels in a path parallelto the long axis of the frame, the chain does not move to a differentsprocket in the pedal sprocket nest.

Referring to FIG. 3D when the base plate is moved in a direction shownas 62, the front portion of the base plate moves in a direction shown as64 b. This causes the chain to also move in the pedal sprocket nest indirection 64 b causing the chain to move to another sprocket in thepedal sprocket nest. The rear pin simply travels in a path parallel tothe long axis of the frame and does not cause the chain to move toanother sprocket in the drive sprocket nest. Therefore, the chain can bemoved from sprocket to sprocket in the pedal nest and the drive nestwith a single derailleur.

Referring to FIG. 5, the chain guide includes a contact surface 70 thatforces the chain upwards causing the chain to contact over ½ theperimeter of the drive sprocket. Because the chain contacts more than ½of the perimeter of the pedal sprocket when there is a pedal sprocketnest, the diameter between sprockets can be increased over traditionalincrements. In one embodiment, the differential between pedal diametersfrom one pedal sprocket to another is increased by thirty percent overtraditional sprocket nests.

The derailleur can be disposed between the perimeter of the largestsprocket of the drive sprocket and the perimeter of the pedal sprocket.In one embodiment, a pedal sprocket nest is carried by the frame and thederailleur is disposed between the largest sprocket of the drivesprocket nest and the largest sprocket of the pedal sprocket nest.

Referring to FIG. 6, the top plate 80 in attached to the derailleur andcarried by the base plate. A top slot 82 is defined in the derailleurand received pin 84 which is carried by the frame. When the derailleuris moved in a direction shown as 92, the pin and top slot cooperate tomove the chain guide laterally in a direction shown as 86 causing thechain to move from one sprocket to another in the drive sprocket nest.

One embodiment of the invention as described herein, is directed to ascooter; as used herein, a scooter is a vehicle having typically twowheels, but could have three, but is so designed to have the riderstanding on the pedals. The use of pneumatic tires, solid rubber orurethane tires, does not change the device from a scooter to a bicycle.It is understood, however, the present invention with the addition of aseat for the rider, would take on the appearance of a pedal drivebicycle, as such the use of the present invention with a seat would alsobe considered within the scope of the present invention, but it must beappreciated that the maximum driving speed of the rear wheel is mosteasily performed standing. The vehicle can be motorized or non-motorized

Variations in the present invention are possible in light of thedescription provided herein. While certain representative embodimentsand details have been shown for the purpose of illustrating the subjectinvention, it will be apparent to those skilled in this art that variouschanges and modifications can be made therein without departing from thescope of the subject invention. It is, therefore, to be understood thatchanges can be made in the particular embodiments described which willbe within the fully intended scope of the invention as defined by thefollowing appended claims.

What is claimed is:
 1. A self-powered non-motorized vehicle having aframe, a steerable front wheel carried by the frame, and a rear wheelcarried by the frame, the rear wheel linked to the drive axle,comprising: a drive sprocket nest attached to the rear wheel so thatwhen rotational force is applied to the drive sprocket nest the rearwheel rotates causing locomotion; a pedal sprocket carried by the frameand linked to said drive sprocket nest by a chain so that when arotational force is applied to said pedal sprocket, said pedal sprocketrotates causing said drive sprocket nest to rotate; a derailleur carriedby said frame and positioned forward of said drive sprocket nest andrearward of said pedal sprocket; and, a chain guide that when saidderailleur is moved laterally to a long axis of said frame, said chainmoves between sprockets on said drive sprocket nest.
 2. The vehicle ofclaim 1 wherein said chain guide includes a chain guide surface whichcauses said chain to contact over ½ the perimeter of a sprocket of saiddrive sprocket nest when said chain is engaged with said sprocket. 3.The vehicle of claim 1 including a tension member carried by said framecausing said chain to contact over ½ the perimeter of said pedalsprocket decreasing the likelihood of the chain slipping off saidsprocket.
 4. The vehicle of claim 1 wherein said derailleur is disposedin a shifting area.
 5. The vehicle of claim 4 wherein said shifting areais defined by a line vertically intersecting the forward most perimeterof the largest sprocket of said drive sprocket nest, a line connectinggenerally the top perimeter of said pedal sprocket and said largestsprocket of said drive sprocket nest, a line vertically intersectingsaid pedal sprocket and a line connecting generally the bottom perimeterof said pedal sprocket and said largest sprocket of said drive sprocketnest.
 6. The vehicle of claim 1 including: a base plate included in saidderailleur wherein said base plate has a first slot and a second slotwherein said second slot is generally a “Z” configuration; and, a firstpin received in said first slot for guiding said base plate along a pathand a second pin received in said second slot for guiding said baseplate along said path wherein said.
 7. The vehicle of claim 6 whereinsaid first slot is generally a “Z” configuration.
 8. The vehicle ofclaim 7 wherein said first slot and said second slot are offset about 45degrees.
 9. The vehicle of claim 1 wherein said derailleur is disposedforward of the perimeter of the largest sprocket of said drive sprocketnest and rearward of said pedal sprocket perimeter.
 10. The vehicle ofclaim 1 including a pedal sprocket nest carried by said frame so thatwhen said derailleur moves in a lateral direction in relation to a longaxis of the frame, the chain moves from one sprocket to another of saidpedal sprocket nest.
 11. A derailleur used with a vehicle where saidvehicle includes a frame, front steerable wheel carried by the frame,pedal sprocket carried by said frame, rear wheel carried by the frame, adrive axle carried by the frame, a drive sprocket nest carried by theframe and connected to said real wheel, a chain linking said pedalsprocket by a chain to said drive sprocket nest comprising: a base platehaving a first slot for receiving a first pin carried by said framecausing a portion of said base plate to travel along a pathcorresponding to said first slot.; a second slot for receiving a secondpin carried by said frame causing a portion of said base plate to travelalong a path corresponding to said second slot wherein said second slotis generally a “Z” configuration and when said base plate travels alongsaid path corresponding to said second slot, said base plate moveslaterally in relation to a long axis of said frame; and, a chain guideattached to said base plate for causing the chain to move laterally inrelation to said long axis of said frame when said base plate travelsalong said path thereby causing the chain to move from one sprocket inthe drive sprocket nest to another sprocket.
 12. The derailleur of claim11 including a chain guide surface included in said chain guide causingsaid chain to contact over ½ the perimeter of a sprocket of said drivesprocket nest when said chain is engaged with said sprocket.
 13. Thederailleur of claim 11 including a pedal sprocket nest carried by saidframe wherein said chain guide causes the chain to move from onesprocket to another in said pedal sprocket nest when said base platemoves laterally in relation to said long axis of said frame.
 13. Thederailleur of claim 11 including a second chain guide for guiding saidchain from sprocket to sprocket on said pedal sprocket nest.
 14. Thederailleur of claim 11 including a tension member carried by said framecausing said chain to contact over ½ the perimeter of said pedalsprocket decreasing the likelihood of the chain slipping off saidsprocket.
 15. The derailleur of claim 11 wherein said derailleur isdisposed between the perimeter of said largest sprocket of said drivesprocket nest and the perimeter of said pedal sprocket.
 16. Thederailleur of claim 11 including a top plate carried by said base platehaving a top slot for receiving a top pin carried by said frame causingsaid top plate to travel along a path corresponding with said top slot.17. A derailleur comprising: a base plate disposed between the perimeterof a drive sprocket nest and a pedal sprocket; a chain guide attached tosaid base plate for moving a chain laterally causing said chain to movefrom sprocket to sprocket in a sprocket nest; a chain guide surfaceincluded in said chain guide for causing said chain to contact over ½the perimeter of said pedal sprocket decreasing the likelihood of thechain slipping off said sprocket; and, a tension member attached to saidbase plate for removing slack in a chain as the chain moves from alarger sprocket to a smaller sprocket.
 18. The derailleur of claim 17including a first “Z” slot defined in said base plate so that when saidbase plate moves award the drive sprocket nest and toward the pedalsprocket, said chain guide moves laterally causing the chain to movefrom sprocket to sprocket in the drive sprocket nest.
 19. The derailleurof claim 18 including a second “Z” slot defined in said base plate sothat when said base plate moves away the drive sprocket nest and towardthe pedal sprocket, said chain guide moves laterally causing the chainto move from sprocket to sprocket in a pedal sprocket nest.
 20. Thederailleur of claim 19 wherein said first and said second slot areoffset about 45 degrees allowing said base plate to move sprockets inthe pedal sprocket nest and the drive sprocket nest independently.